This application relates generally to sea water desalination kits being used for naval rescue equipment or as an emergency water purifier.
The application relates also to a method for producing, by means of natural osmosis, a nutritious drink out of non-potable, water-containing liquids.
To date, there exist two different types of desalination kits being small enough to be suitable as naval rescue equipment: devices making use of chemical treatments of sea water, and inflatable distilling devices energized by the sun.
The latter devices are not foolproof, they are very delicate, and all depend on sunlight and on very slow seaway. Therefore, the chemical treatment of sea water is preferred. The disadvantage of the chemical method is the high price of the chemicals (up to several hundred dollars for desalting 1000 g of sea water).
Another disadvantage is poor taste and sometimes even harmful effects of the portable water produced by such a chemical treatment.
Another disadvantage is the high dead weight of such a chemical desalination kit, varying between 250 g and 350 g for producing 1000 g of potable water.
Hence, the weight advantage of such chemical desalination kits for the emergency rations of potable water is limited, and considering the high price of those chemical desalination kits, simple emergency rations of potable water are preferred.
The object of my invention is a method and an apparatus for producing, by means of natural osmosis, a tasty and nutritious drink from sea water or other non-potable watercontaining liquid.
Another object of my invention is to provide an apparatus of this kind which is inexpensive, foolproof, light (about 150 g for producing 1000 g of nutritious drink), and storable for considerable periods of time.
This invention does not relate to methods and/or apparatus working by means of reverse osmosis, ultrafiltration or dialysis, and it does not relate to any method and/or apparatus using membranes which are substantially permeable to salts.
The phenomenon of natural osmosis is generally known and has been used for various test and measuring instruments.
Today those instruments are generally replaced by electronic or electric instruments.
In recent years, attempts have been made for using natural osmosis for producing potable liquids out of sea water and/or other kinds of non-potable liquids.
Most of these approaches were made by military research centers trying to develop an emergency desalination kit as a component of the naval rescue equipment of air forces and navies.
Another approach using osmosis is described by William T. Hough (U.S. Pat. Nos. 3,696,931 and 3,702,820). The Hough patents disclose different types of vessels having an osmotic membrane as an enclosing part thereof. In such a vessel, a comestible solute or solution is enclosed or can be filled in. The Hough patents also disclose that "the comestible solute is a human food of any type, provided it is soluble in water", and list about 12 examples of food materials.
Recent experiments have shown that only some of those disclosed comestible solutes or solutions are suitable for preparing, by natural osmosis from fresh water or brackish water, a diluted comestible solution, but none of those listed foods is suitable for preparing such a diluted comestible solution from real sea water (which is known to contain 3.5-4% of salts). This is because the desalination of real sea water by means of natural osmosis requires a comestible solute or solution with much higher osmosis efficiency than required for the desalination of slightly salty water.
A comestible solute or solution with such a high osmotic efficiency has not yet been found, and therefore the prior-art approach is absolutely inoperable for desalination of real sea water.
The prior-art patents fail to disclose any method or arrangement how the comestible solute or solution can be stored inside the vessel for long periods of time without drying out (and thus destroying) the wet semipermeable membrane during the storage time.